1. Field of the Invention
The present invention relates to light-emitting devices and lighting devices each using a solid light-emitting element.
2. Description of the Related Art
In a solid light-emitting element in which light is emitted in a medium having higher refractive index than air, incident light from a high refractive index region to a low refractive index region with an angle larger than the critical angle is fully reflected on an interface. A variety of techniques has been developed in order to extract light of the solid light-emitting element efficiently.
For example, a technique is known in which incident light to a low refractive index region with an angle larger than the critical angle is prevented from being fully reflected repeatedly with the use of a structure in which a high refractive index region is connected to the low refractive index region via an interface that has an uneven structure.
In Non-Patent Document 1, a structure is employed in which a high refractive index glass substrate is combined with a high refractive index lens as a means for increasing light extraction efficiency of a solid light-emitting element.